Design, fabrication, testing, and conditioning of micro-components for use in a light-emitting panel

ABSTRACT

A method of forming micro-components is disclosed. The method includes pretesting and conditioning of the micro-components. The micro-components that fail testing or conditioning are discarded, and those remaining are assembled into a panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.09/697,358 entitled “A Micro-Component for Use in a Light-EmittingPanel,” filed Oct. 27, 2000, and claims priority to that parentapplication's filing date. Also referenced hereby are the followingapplications which are incorporated herein by reference in theirentireties, and the filing dates thereof to which priority is alsoclaimed: U.S. patent application Ser. No. 09/697,344 entitled “ALight-Emitting Panel and a Method for Making,” filed Oct. 27, 2000; U.S.patent application Ser. No. 09/697,498 entitled “A Method for Testing aLight-Emitting Panel and the Components Therein,” filed Oct. 27, 2000;U.S. patent application Ser. No. 09/697,345 entitled “A Method andSystem for Energizing a Micro-Component in a Light-Emitting Panel,”filed Oct. 27, 2000; U.S. patent application Ser. No. 09/697,346entitled “A Socket for Use in a Light-Emitting Panel,” filed Oct. 27,2000; U.S. patent application Ser. No. (Attorney Docket No.SAIC0029-CIP2) entitled “Use of Printing and Other Technology forMicro-Component Placement,” filed concurrently herewith; U.S. patentapplication Ser. No. (Attorney Docket No. SAIC0029-CIP1) entitled“Liquid Manufacturing Processes for Panel Layer Fabrication,” filedconcurrently herewith; U.S. patent application Ser. No. (Attorney DocketNo. SAIC0025-CIP) entitled “Method for On-Line Testing of aLight-Emitting Panel,” filed concurrently herewith; and U.S. patentapplication Ser. No. (Attorney Docket No. SAIC0026-CIP) entitled “Methodand Apparatus for Addressing Micro-Components in a Plasma DisplayPanel,” filed concurrently herewith.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting panel and methods offabricating the same. The present invention further relates to amicro-component for use in a light-emitting panel.

2. Description of Related Art

In a typical plasma display, a gas or mixture of gases is enclosedbetween orthogonally crossed and spaced conductors. The crossedconductors define a matrix of cross over points, arranged as an array ofminiature picture elements (pixels), which provide light. At any givenpixel, the orthogonally crossed and spaced conductors function asopposed plates of a capacitor, with the enclosed gas serving as adielectric. When a sufficiently large voltage is applied, the gas at thepixel breaks down creating free electrons that are drawn to the positiveconductor and positively charged gas ions that are drawn to thenegatively charged conductor. These free electrons and positivelycharged gas ions collide with other gas atoms causing an avalancheeffect creating still more free electrons and positively charged ions,thereby creating plasma. The voltage level at which this plasma-formingdischarge occurs is called the write voltage.

Upon application of a write voltage, the gas at the pixel ionizes andemits light only briefly as free charges formed by the ionizationmigrate to the insulating dielectric walls of the cell where thesecharges produce an opposing voltage to the applied voltage and therebyeventually extinguish the discharge. Once a pixel has been written, acontinuous sequence of light emissions can be produced by an alternatingsustain voltage. The amplitude of the sustain waveform can be less thanthe amplitude of the write voltage, because the wall charges that remainfrom the preceding write or sustain operation produce a voltage thatadds to the voltage of the succeeding sustain waveform applied in thereverse polarity to produce the ionizing voltage. Mathematically, theidea can be set out as V_(s)=V_(w)−V_(wall), where V_(s) is the sustainvoltage, V_(w) is the write voltage, and V_(wall) is the wall voltage.Accordingly, a previously unwritten (or erased) pixel cannot be ionizedby the sustain waveform alone. An erase operation can be thought of as awrite operation that proceeds only far enough to allow the previouslycharged cell walls to discharge; it is similar to the write operationexcept for timing and amplitude.

Typically, there are two different arrangements of conductors that areused to perform the write, erase, and sustain operations. The one commonelement throughout the arrangements is that the sustain and the addresselectrodes are spaced apart with the plasma-forming gas in between.Thus, at least one of the address or sustain electrodes may be locatedpartially within the path the radiation travels, when the plasma-forminggas ionizes, as it exits the plasma display. Consequently, transparentor semi-transparent conductive materials must be used, such as indiumtin oxide (ITO), so that the electrodes do not interfere with thedisplayed image from the plasma display. Using ITO, however, has severaldisadvantages, for example, ITO is expensive and adds significant costto the manufacturing process and ultimately the final plasma display.

The first arrangement uses two orthogonally crossed conductors, oneaddressing conductor and one sustaining conductor. In a gas panel ofthis type, the sustain waveform is applied across all the addressingconductors and sustain conductors so that the gas panel maintains apreviously written pattern of light emitting pixels. For a conventionalwrite operation, a suitable write voltage pulse is added to the sustainvoltage waveform so that the combination of the write pulse and thesustain pulse produces ionization. In order to write an individual pixelindependently, each of the addressing and sustain conductors has anindividual selection circuit. Thus, applying a sustain waveform acrossall the addressing and sustain conductors, but applying a write pulseacross only one addressing and one sustain conductor will produce awrite operation in only the one pixel at the intersection of theselected addressing and sustain conductors.

The second arrangement uses three conductors. In panels of this type,called coplanar sustaining panels, each pixel is formed at theintersection of three conductors, one addressing conductor and twoparallel sustaining conductors. In this arrangement, the addressingconductor orthogonally crosses the two parallel sustaining conductors.With this type of panel, the sustain function is performed between thetwo parallel sustaining conductors and the addressing is done by thegeneration of discharges between the addressing conductor and one of thetwo parallel sustaining conductors.

The sustaining conductors are of two types, addressing-sustainingconductors and solely sustaining conductors. The function of theaddressing-sustaining conductors is twofold: to achieve a sustainingdischarge in cooperation with the solely sustaining conductors; and tofulfill an addressing role. Consequently, the addressing-sustainingconductors are individually selectable so that an addressing waveformmay be applied to any one or more addressing-sustaining conductors. Thesolely sustaining conductors, on the other hand, are typically connectedin such a way that a sustaining waveform can be simultaneously appliedto all of the solely sustaining conductors so that they can be carriedto the same potential in the same instant.

Numerous types of plasma panel display devices have been constructedwith a variety of methods for enclosing a plasma-forming gas betweensets of electrodes. In one type of plasma display panel, parallel platesof glass with wire electrodes on the surfaces thereof are spaceduniformly apart and sealed together at the outer edges with theplasma-forming gas filling the cavity formed between the parallelplates. Although widely used, this type of open display structure hasvarious disadvantages. The sealing of the outer edges of the parallelplates, the pumping down to vacuum, the baking out under vacuum, and theintroduction of the plasma-forming gas are both expensive andtime-consuming processes, resulting in a costly end product. Inaddition, it is particularly difficult to achieve a good seal at thesites where the electrodes are fed through the ends of the parallelplates. This can result in gas leakage and a shortened productlifecycle. Another disadvantage is that individual pixels are notsegregated within the parallel plates. As a result, gas ionizationactivity in a selected pixel during a write operation may spill over toadjacent pixels, thereby raising the undesirable prospect of possiblyigniting adjacent pixels without a write pulse being applied. Even ifadjacent pixels are not ignited, the ionization activity can change theturn-on and turn-off characteristics of the nearby pixels.

In another type of known plasma display, individual pixels aremechanically isolated either by forming trenches in one of the parallelplates or by adding a perforated insulating layer sandwiched between theparallel plates. These mechanically isolated pixels, however, are notcompletely enclosed or isolated from one another because there is a needfor the free passage of the plasma-forming gas between the pixels toassure uniform gas pressure throughout the panel. While this type ofdisplay structure decreases spill over, spill over is still possiblebecause the pixels are not in total physical isolation from one another.In addition, in this type of display panel it is difficult to properlyalign the electrodes and the gas chambers, which may cause pixels tomisfire. As with the open display structure, it is also difficult to geta good seal at the plate edges. Furthermore, it is expensive and timeconsuming to pump down to vacuum, bake out under vacuum, introduce theplasma producing gas and seal the outer edges of the parallel plates.

In yet another type of known plasma display, individual pixels are alsomechanically isolated between parallel plates. In this type of display,the plasma-forming gas is contained in transparent spheres formed of aclosed transparent shell. Various methods have been used to contain thegas filled spheres between the parallel plates. In one method, spheresof varying sizes are tightly bunched and randomly distributed throughouta single layer, and sandwiched between the parallel plates. In a secondmethod, spheres are embedded in a sheet of transparent dielectricmaterial and that material is then sandwiched between the parallelplates. In a third method, a perforated sheet of electricallynonconductive material is sandwiched between the parallel plates withthe gas filled spheres distributed in the perforations.

While each of the types of displays discussed above are based ondifferent design concepts, the manufacturing approach used in theirfabrication is generally the same. Conventionally, a batch fabricationprocess is used to manufacture these types of plasma panels. As is wellknown in the art, in a batch process individual component parts arefabricated separately, often in different facilities and by differentmanufacturers, and then brought together for final assembly whereindividual plasma panels are created one at a time. Batch processing hasnumerous shortcomings, such as, for example, the length of timenecessary to produce a finished product. Long cycle times increaseproduct cost and are undesirable for numerous additional reasons knownin the art. For example, a sizeable quantity of substandard, defective,or useless fully or partially completed plasma panels may be producedduring the period between detection of a defect or failure in one of thecomponents and an effective correction of the defect or failure.

This is especially true of the first two types of displays discussedabove; the first having no mechanical isolation of individual pixels,and the second with individual pixels mechanically isolated either bytrenches formed in one parallel plate or by a perforated insulatinglayer sandwiched between two parallel plates. Due to the fact thatplasma-forming gas is not isolated at the individual pixel/subpixellevel, the fabrication process precludes the majority of individualcomponent parts from being tested until the final display is assembled.Consequently, the display can only be tested after the two parallelplates are sealed together and the plasma-forming gas is filled insidethe cavity between the two plates. If post production testing shows thatany number of potential problems have occurred, (e.g. poor luminescenceor no luminescence at specific pixels/subpixels) the entire display isdiscarded.

BRIEF SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide a light-emittingpanel that may be used as a large-area radiation source, for energymodulation, for particle detection and as a flat-panel display.Gas-plasma panels are preferred for these applications due to theirunique characteristics.

In one basic form, the light-emitting panel may be used as a large arearadiation source. By configuring the light-emitting panel to emitultraviolet (UV) light, the panel has application for curing paint orother coatings, and for sterilization. With the addition of one or morephosphor coatings to convert the UV light to visible white light, thepanel also has application as an illumination source.

In addition, the light-emitting panel may be used as a plasma-switchedphase array by configuring the panel in at least one embodiment in amicrowave transmission mode. The panel is configured in such a way thatduring ionization the plasma-forming gas creates a localized index ofrefraction change for the microwaves (although other electromagneticwavelengths would work). The microwave beam from the panel can then besteered or directed in any desirable pattern by introducing at alocalized area a phase shift and/or directing the microwaves out of aspecific aperture in the panel

Additionally, the light-emitting panel may be used for particle/photondetection. In this embodiment, the light-emitting panel is subjected toa potential that is just slightly below the write voltage required forionization. When the device is subjected to outside energy at a specificposition or location in the panel, that additional energy causes theplasma-forming gas in the specific area to ionize, thereby providing ameans of detecting outside energy.

Further, the light-emitting panel may be used in flat-panel displays.These displays can be manufactured very thin and lightweight, whencompared to similar sized cathode ray tube (CRTs), making them ideallysuited for home, office, theaters and billboards. In addition, thesedisplays can be manufactured in large sizes and with sufficientresolution to accommodate high-definition television (HDTV). Gas-plasmapanels do not suffer from electromagnetic distortions and are,therefore, suitable for applications strongly affected by magneticfields, such as military applications, radar systems, railway stationsand other underground systems.

According to a general embodiment of the present invention, alight-emitting panel is made from two substrates, wherein one of thesubstrates includes a plurality of sockets and wherein at least twoelectrodes are disposed. At least partially disposed in each socket is amicro-component, although more than one micro-component may be disposedtherein. Each micro-component includes a shell at least partially filledwith a gas or gas mixture capable of ionization. When a large enoughvoltage is applied across the micro-component the gas or gas mixtureionizes forming plasma and emitting radiation.

In one embodiment of the present invention, the micro-component isconfigured to emit ultra-violet (UV) light, which may be converted tovisible light by at least partially coating each micro-component withphosphor. To obtain an improvement in the discharge characteristics,each micro-component may be at least partially coated with a secondaryemission enhancement material.

In another embodiment, each micro-component is at least partially coatedwith a reflective material. An index matching material is disposed so asto be in contact with at least a portion of the reflective material. Thecombination of the index matching material and the reflective materialpermits a predetermined wavelength of light to be emitted from eachmicro-component at the point of contact between the index matchingmaterial and the reflective material.

Another object of the present invention is to provide a micro-componentfor use in a light-emitting panel. A shell at least partially filledwith at least one plasma-forming gas provides the basic micro-componentstructure. The shell may be doped or ion implanted with a conductivematerial, a material that provides secondary emission enhancement,and/or a material that converts UV light to visible light. Themicro-components will be made as a sphere, cylinder or any other shape.The size and shape will be determined in accordance with the desiredresolution for the display panel to be assembled. Typical sizes areabout hundreds of microns independent of shape.

Another preferred embodiment of the present invention is to provide amethod of making a micro-component. In one embodiment, the method ispart of a continuous process, where a shell is at least partially formedin the presence of at least one plasma-forming gas, such that whenformed, the shell is filled with the plasma-forming gas or gas mixture.

In another embodiment, the micro-component is made by affixing a firstsubstrate to a second substrate in the presence of at least oneplasma-forming gas. In this method, either the first and/or the secondsubstrate contains a plurality of cavities so that when the firstsubstrate is affixed to the second substrate the plurality of cavitiesare filled with the plasma-forming gas or gas mixture. In a preferredembodiment, a first substrate is advanced through a first rollerassembly, which includes a roller with a plurality of nodules and aroller with a plurality of depressions. Both the plurality of nodulesand the plurality of depressions are in registration with each other sothat when the first substrate passes through the first roller assembly,the first substrate has a plurality of cavities formed therein. A secondsubstrate is advanced through a second roller assembly and then affixedto the first substrate in the presence of at least one gas so that whenthe two substrates are affixed the cavities are filled with the gas orgas mixture. In an alternate preferred embodiment, the second rollerassembly includes a roller with a plurality of nodules and a roller witha plurality of depressions so that when the second substrate passesthrough the second roller assembly, the second substrate also has aplurality of cavities formed therein. In either of these embodiments, atleast one electrode may be sandwiched between the first and secondsubstrates prior to the substrates being affixed.

In another embodiment, at least one substrate is thermally treated inthe presence of a least one plasma-forming gas so as to form shellsfilled with the plasma-forming gas or gas-mixture.

In a specific aspect, the micro-components, whether sphere, capillary orother shape are coated with a frequency converting coating. Phosphor isan example of such a coating. More specifically, the coating convertselectromagnetic radiation generated in the plasma in the ultravioletregion of the spectrum, and converts it to the visible red, blue orgreen region of the spectrum.

Alternatives include putting a drop of the frequency converting materialin a socket into which the micro-component is placed, or themicro-component itself can be doped with a material such as a rare earththat is a frequency converter. Examples of materials include bariumfluoride or the like, yttrium aluminum garnet, or gadolinium galliumgarnet. The plasma gases in the micro-component can include xenonchloride, argon chloride, etc., namely the rare gas halides.

In another aspect, the micro-components are tested as they aremanufactured. The micro-components are optionally scanned for certainphysical characteristics or defects, for example, in an optical fielddetecting shape such as sphericity and size as they drop through atower. A micro-component displacement device can be used to remove thosethat are bad. At a subsequent layer, as they drop the micro-componentsare subjected to electron beam excitation, microwave or RF field, forexample, to excite the gas. Another physical characteristic or defect istested, such as if a certain luminous output is achieved, and ifachieved, it is preliminarily accepted. Those for which a desiredluminous output is not achieved are discarded, for example, through theuse of a second micro-component displacement device.

In yet still another aspect, the micro-components are preconditioned bybeing excited for a predetermined period of time. Examples includetaking the micro-components that passed the initial test, placing themin a container and exciting them, for example, for 5 to 10 hours.Alternatively, they can be placed between large parallel electrodes.After the batch run, they are dropped through a tower as they areexcited, output detected and the ones that do not excite are knocked outof the stream.

Other features, advantages, and embodiments of the invention are setforth in part in the description that follows, and in part, will beobvious from this description, or may be learned from the practice ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of this invention willbecome more apparent by reference to the following detailed descriptionof the invention taken in conjunction with the accompanying drawings.

FIG. 1 shows a socket with a micro-component disposed therein.

FIG. 2 depicts a portion of a light-emitting panel showing a pluralityof micro-components disposed in sockets.

FIG. 3A shows an example of a cavity that has a cube shape.

FIG. 3B shows an example of a cavity that has a cone shape.

FIG. 3C shows an example of a cavity that has a conical frustum shape.

FIG. 3D shows an example of a cavity that has a paraboloid shape.

FIG. 3E shows an example of a cavity that has a spherical shape.

FIG. 3F shows an example of a cavity that has a hemi-cylindrical shape.

FIG. 3G shows an example of a cavity that has a pyramid shape.

FIG. 3H shows an example of a cavity that has a pyramidal frustum shape.

FIG. 3I shows an example of a cavity that has a parallelepiped shape.

FIG. 3J shows an example of a cavity that has a prism shape.

FIG. 4 shows an apparatus used in an embodiment of the present inventionas part of a continuous process for forming micro-components.

FIG. 5 shows an apparatus used in an embodiment of the present inventionas part of another process for forming micro-components.

FIG. 6 shows an variation of the apparatus shown in FIG. 5, which isused as part of another process for forming micro-components.

FIG. 7 illustrates an example of selection of pixel size andmicro-component (micro-sphere) size for different sized high definitiontelevision (HDTV) displays, which can be manufactured according to themicro-component method hereof.

FIG. 8 is a table showing numbers of pixels for various standard displayresolutions.

FIG. 9 illustrates, according to an embodiment, one way in which anelectrode may be disposed between two substrates as part of a processfor forming micro-components.

FIG. 10 depicts the steps of another method for formingmicro-components.

FIG. 11 shows an apparatus used in an embodiment of the presentinvention as part of a continuous process for forming micro-componentssimilar to that of FIG. 4, and including a mechanism for pretesting orpre-screening of micro-components prior to assembly in a panel.

FIG. 12 shows an apparatus used for batch conditioning ofmicro-components.

FIG. 13 shows an alternative embodiment of an apparatus used for batchconditioning of micro-components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

As embodied and broadly described herein, the preferred embodiments ofthe present invention are directed to a novel light-emitting panel. Inparticular, the preferred embodiments are directed to a micro-componentcapable of being used in the light-emitting panel and at least partiallydisposed in at least one socket.

FIGS. 1 and 2 show two embodiments of the present invention wherein alight-emitting panel includes a first substrate 10 and a secondsubstrate 20. The first substrate 10 may be made from silicates,polypropylene, quartz, glass, any polymeric-based material or anymaterial or combination of materials known to one skilled in the art.Similarly, second substrate 20 may be made from silicates,polypropylene, quartz, glass, any polymeric-based material or anymaterial or combination of materials known to one skilled in the art.First substrate 10 and second substrate 20 may both be made from thesame material or each of a different material. Additionally, the firstand second substrate may be made of a material that dissipates heat fromthe light-emitting panel. In a preferred embodiment, each substrate ismade from a material that is mechanically flexible.

The first substrate 10 includes a plurality of sockets 30. A cavity 55formed within and/or on the first substrate 10 provides the basic socket30 structure. The cavity 55 may be any shape and size. As depicted inFIGS. 3A-3J, the shape of the cavity 55 may include, but is not limitedto, a cube 100, a cone 110, a conical frustum 120, a paraboloid 130,spherical 140, cylindrical 150, a pyramid 160, a pyramidal frustum 170,a parallelepiped 180, or a prism 190. The size and shape of the socket30 influence the performance and characteristics of the light-emittingpanel and are selected to optimize the panel's efficiency of operation.In addition, socket geometry may be selected based on the shape and sizeof the micro-component to optimize the surface contact between themicro-component and the socket and/or to ensure connectivity of themicro-component and any electrodes disposed within the socket. Further,the size and shape of the sockets 30 may be chosen to optimize photongeneration and provide increased luminosity and radiation transportefficiency.

At least partially disposed in each socket 30 is at least onemicro-component 40. Multiple micro-components may be disposed in asocket to provide increased luminosity and enhanced radiation transportefficiency. In a color light-emitting panel according to one embodimentof the present invention, a single socket supports threemicro-components configured to emit red, green, and blue light,respectively. The micro-components 40 may be of any shape, including,but not limited to, spherical, cylindrical, and aspherical. In addition,it is contemplated that a micro-component 40 includes a micro-componentplaced or formed inside another structure, such as placing a sphericalmicro-component inside a cylindrical-shaped structure. In a colorlight-emitting panel according to an embodiment of the presentinvention, each cylindrical-shaped structure holds micro-componentsconfigured to emit a single color of visible light or multiple colorsarranged red, green, blue, or in some other suitable color arrangement.

In another embodiment of the present invention, an adhesive or bondingagent is applied to each micro-component to assist in placing/holding amicro-component 40 or plurality of micro-components in a socket 30. Inan alternative embodiment, an electrostatic charge is placed on eachmicro-component and an electrostatic field is applied to eachmicro-component to assist in the placement of a micro-component 40 orplurality of micro-components in a socket 30. Applying an electrostaticcharge to the micro-components also helps avoid agglomeration among theplurality of micro-components. In one embodiment of the presentinvention, an electron gun is used to place an electrostatic charge oneach micro-component and one electrode disposed proximate to each socket30 is energized to provide the needed electrostatic field required toattract the electrostatically charged micro-component.

In its most basic form, each micro-component 40 includes a shell 50filled with a plasma-forming gas or gas mixture 45. Any suitable gas orgas mixture 45 capable of ionization may be used as the plasma-forminggas, including, but not limited to, krypton, xenon, argon, neon, oxygen,helium, mercury, and mixtures thereof. In fact, any noble gas could beused as the plasma-forming gas, including, but not limited to, noblegases mixed with cesium or mercury. Further, rare gas halide mixturessuch as xenon chloride, xenon fluoride and the like are also suitableplasma-forming gases. Rare gas halides are efficient radiators havingradiating wavelengths of approximately 300 to 350 nm, which is longerthan that of pure xenon (147 to 170 nm). This results in an overallquantum efficiency gain, ie., a factor of two or more, given by themixture ratio. Still further, in another embodiment of the presentinvention, rare gas halide mixtures are also combined with otherplasma-forming gases as listed above. This description is not intendedto be limiting. One skilled in the art would recognize other gasses orgas mixtures that could also be used. In a color display, according toanother embodiment, the plasma-forming gas or gas mixture 45 is chosenso that during ionization the gas will irradiate a specific wavelengthof light corresponding to a desired color. For example, neon-argon emitsred light, xenon-oxygen emits green light, and krypton-neon emits bluelight. While a plasma-forming gas or gas mixture 45 is used in apreferred embodiment, any other material capable of providingluminescence is also contemplated, such as an electro-luminescentmaterial, organic light-emitting diodes (OLEDs), or an electro-phoreticmaterial.

The shell 50 may be made from a wide assortment of materials, including,but not limited to, silicates, polypropylene, glass, any polymeric-basedmaterial, magnesium oxide and quartz and may be of any suitable size.The shell 50 may have a diameter ranging from micrometers to centimetersas measured across its minor axis, with virtually no limitation as toits size as measured across its major axis. For example, acylindrical-shaped micro-component may be only 100 microns in diameteracross its minor axis, but may be hundreds of meters long across itsmajor axis. In a preferred embodiment, the outside diameter of theshell, as measured across its minor axis, is from 100 microns to 300microns. In addition, the shell thickness may range from micrometers tomillimeters, with a preferred thickness from 1 micron to 10 microns.

When a sufficiently large voltage is applied across the micro-componentthe gas or gas mixture ionizes forming plasma and emitting radiation. InFIG. 2, a two electrode configuration is shown including a first sustainelectrode 520 and an address electrode 530. In FIG. 1, a three electrodeconfiguration is shown, wherein a first sustain electrode 520, anaddress electrode 530 and a second sustain electrode 540 are disposedwithin a plurality of material layers 60 that form the first substrate10. The potential required to initially ionize the gas or gas mixtureinside the shell 50 is governed by Paschen's Law and is closely relatedto the pressure of the gas inside the shell. In the present invention,the gas pressure inside the shell 50 ranges from tens of torrs toseveral atmospheres. In a preferred embodiment, the gas pressure rangesfrom 100 torr to 700 torr or higher pressure as appropriate. The sizeand shape of a micro-component 40 and the type and pressure of theplasma-forming gas contained therein, influence the performance andcharacteristics of the light-emitting panel and are selected to optimizethe panel's efficiency of operation.

There are a variety of coatings 300 and dopants that may be added to amicro-component 40 that also influence the performance andcharacteristics of the light-emitting panel. The coatings 300 may beapplied to the outside or inside of the shell 50, and may eitherpartially or fully coat the shell 50. Types of outside coatings include,but are not limited to, coatings used to convert UV light to visiblelight (e.g. phosphor), coatings used as reflecting filters, and coatingsused as bandpass filters. Types of inside coatings include, but are notlimited to, coatings used to convert UV light to visible light (e.g.phosphor), coatings used to enhance secondary emissions and coatingsused to prevent erosion. One skilled in the art will recognize thatother coatings may also be used. The coatings 300 may be applied to theshell 50 by differential stripping, lithographic process, sputtering,laser deposition, chemical deposition, vapor deposition, or depositionusing ink jet technology. One skilled in the art will realize that othermethods of coating the inside and/or outside of the shell 50 may alsowork. Types of dopants include, but are not limited to, dopants used toconvert UV light to visible light (e.g. phosphor), dopants used toenhance secondary emissions and dopants used to provide a conductivepath through the shell 50. The dopants are added to the shell 50 by anysuitable technique known to one skilled in the art, including ionimplantation. It is contemplated that any combination of coatings anddopants may be added to a micro-component 40.

In an embodiment of the present invention, when a micro-component isconfigured to emit UV light, the UV light is converted to visible lightby at least partially coating the inside of the shell 50 with phosphor,at least partially coating the outside of the shell 50 with phosphor,doping the shell 50 with phosphor and/or coating the inside of a socket30 with phosphor. In a color panel, according to an embodiment of thepresent invention, colored phosphor is chosen so the visible lightemitted from alternating micro-components is colored red, green andblue, respectively. By combining these primary colors at varyingintensities, all colors can be formed. It is contemplated that othercolor combinations and arrangements may be used.

To obtain an improvement in discharge characteristics, in an embodimentof the present invention, the shell 50 of each micro-component 40 is atleast partially coated on the inside surface with a secondary emissionenhancement material. Any low affinity material may be used including,but not limited to, magnesium oxide and thulium oxide. One skilled inthe art would recognize that other materials will also provide secondaryemission enhancement. In another embodiment of the present invention,the shell 50 is doped with a secondary emission enhancement material. Itis contemplated that the doping of shell 50 with a secondary emissionenhancement material may be in addition to coating the shell 50 with asecondary emission enhancement material. In this case, the secondaryemission enhancement material used to coat the shell 50 and dope theshell 50 may be different.

Alternatively to the previously discussed phosphor which can be used tocoat the micro-component, or alternatively, placed into a socket in adisplay panel in which the micro-components are placed, themicro-component material can be doped with a rare earth that is afrequency converter. Such dopants can include barium fluoride or similarmaterials such as yttrium aluminum garnet, or gadolinium gallium garnet.These types of frequency converting materials serve to convert plasmalight at the UV wavelength to visible light of red, blue or green color.The gasses in the micro-component in such cases will include rare gashalide mixtures such as xenon chloride, xenon fluoride and the like.Rare gas halides are efficient radiators having radiating wavelengths ofapproximately 300 to 350 nm, which is longer than that of pure xenon(147 to 170 nm). This results in an overall quantum efficiency gain,i.e., a factor of two or more, given by the mixture ratio. Stillfurther, in another embodiment of the present invention, rare gas halidemixtures are also combined with other plasma-forming gases as listedpreviously. This description is not intended to be limiting. In the casewhen such frequency converting materials are used, instead of using aphosphor coating, they can be integrated as a dopant in the shell of themicro-component. For example, yttrium aluminum garnet doped with ceriumcan serve to convert UV wavelengths from rare gas halides into greenlight.

In addition to, or in place of, doping the shell 50 with a secondaryemission enhancement material, according to an embodiment of the presentinvention, the shell 50 is doped with a conductive material. Possibleconductive materials include, but are not limited to silver, gold,platinum, and aluminum. Doping the shell 50 with a conductive material,either in two or more localized areas to provide separate electrode-likepaths or in a way to produce anisotropic conductivity in the shell (highperpendicular conductivity, low in-plane conductivity), provides adirect conductive path to the gas or gas mixture contained in the shelland provides one possible means of achieving a DC light-emitting panel.In this manner, shorting is avoided and two or more separate electrodepaths are maintained to allow exciting of the gas.

In another embodiment of the present invention, the shell 50 of themicro-component 40 is coated with a reflective material. An indexmatching material that matches the index of refraction of the reflectivematerial is disposed so as to be in contact with at least a portion ofthe reflective material. The reflective coating and index matchingmaterial may be separate from, or in conjunction with, the phosphorcoating and secondary emission enhancement coating of previousembodiments. The reflective coating is applied to the shell 50 in orderto enhance radiation transport. By also disposing an index-matchingmaterial so as to be in contact with at least a portion of thereflective coating, a predetermined wavelength range of radiation isallowed to escape through the reflective coating at the interfacebetween the reflective coating and the index-matching material. Byforcing the radiation out of a micro-component through the interfacearea between the reflective coating and the index-matching materialgreater micro-component efficiency is achieved with an increase inluminosity. In an embodiment, the index matching material is coateddirectly over at least a portion of the reflective coating. In anotherembodiment, the index matching material is disposed on a material layer,or the like, that is brought in contact with the micro-component suchthat the index matching material is in contact with at least a portionof the reflective coating. In another embodiment, the size of theinterface is selected to achieve a specific field of view for thelight-emitting panel.

Several methods are proposed, in various embodiments, for making amicro-component for use in a light-emitting panel. It has beencontemplated that each of the coatings and dopants that may be added toa micro-component 40, as disclosed herein, may also be included in stepsin forming a micro-component, as discussed herein.

In one embodiment of the present invention, a continuous inline processfor making a micro-component is described, where a shell is at leastpartially formed in the presence of at least one plasma-forming gas,such that when formed, the shell is filled with the gas or gas mixture.In a preferred embodiment, the process takes place in a drop tower.According to FIG. 4, and as an example of one of many possible ways tomake a micro-component as part of a continuous inline process, a dropletgenerator 600 including a pressure transducer port 605, a liquid inletport 610, a piezoelectric transducer 615, a transducer drive signalelectrode 620, and an orifice plate 625, produces uniform water dropletsof a predetermined size. The droplets pass through an encapsulationregion 630 where each water droplet is encased in a gel outer membraneformed of an aqueous solution of glass forming oxides (or any othersuitable material that may be used for a micro-component shell), whichis then passed through a dehydration region 640 leaving a hollow dry gelshell. This dry gel shell then travels through a transition region 650where it is heated into a glass shell (or other type of shell dependingon what aqueous solution was chosen) and then finally through a refiningregion 660. While it is possible to introduce a plasma-forming gas orgas mixture into the process during any one of the steps, it ispreferred in an embodiment of the present invention to perform the wholeprocess in the presence of the plasma-forming gas or gas mixture. Thus,when the shell leaves the refining region 660, the plasma-forming gas orgas mixture is sealed inside the shell thereby forming amicro-component.

In an embodiment of the present invention, the above process is modifiedso that the shell can be doped with either a secondary emissionenhancement material and/or a conductive material, although otherdopants may also be used. While it is contemplated that the dopants maybe added to the shell by ion implantation at later stages in theprocess, in a preferred embodiment, the dopant is added directly in theaqueous solution so that the shell is initial formed with the dopantalready present in the shell.

The above process steps may be modified or additional process steps maybe added to the above process for forming a micro-component to provide ameans for adding at least one coating to the micro-component. Forcoatings that may be disposed on the inside of the shell including, butnot limited to a secondary emission enhancement material and aconductive material, it is contemplated in an embodiment of the presentinvention that those coating materials are added to the initial dropletsolution so that when the outer membrane is formed around the initialdroplet and then passed through the dehydration region 640 the coatingmaterial is left on the inside of the hollow dry gel shell. For coatingsthat may be disposed on the outside of the shell including, but notlimited to, coatings used to convert UV light to visible light, coatingsused as reflective filters and coatings used as band-gap filters, it iscontemplated that after the micro-component leaves the refining region660, the micro-component component will travel through at least onecoating region. The coatings may be applied by any number of processesknown to those skilled in the art as a means of applying a coating to asurface.

A further modification of the drop tower of FIG. 4 is illustrated inFIG. 11 with a continuous testing region 801. The continuous testingregion 801 includes a first optical detector 821 which detectsindividual micro-components as they are formed. This optical detectorcan detect such things as sphericity and size in a continuous process,typically operating at about 10 kilohertz sampling rate. Signalsrepresenting the micro-component detected are passed through line 823 toa control module 825. If a micro-component does not meet certain minimumstandards, a signal is sent from control module 825 to mechanicalactuator 827 which activates a micro-component displacement device orarm 829 which is activated to remove the failed micro-component from thestream. A second region of the continuing testing device 801 includes,optionally, electrodes 805 which are excited through leads 807 by powersupply 809 to generate a field which excites the plasma gas within themanufactured micro-components. As the micro-components are exited, aluminous output is generated and a second optical detector 811 serves todetect the luminous output and send a signal representing the luminousoutput for each individual micro-component through line 813 to a secondcontrol unit 815.

If no luminous output is detected or a luminous output of less than apredetermined threshold is detected, the control unit 815 sends a signalto actuator 817 which then actuates a second micro-componentdisplacement device or arm 819 to remove the failed micro-component fromthe stream.

With respect to the photo-detectors, they are conventional, and can beof the type, for example, which detect UV light. Alternatively, if themicro-component has been coated prior to the end of the fabricationprocess, for example, with phosphor, the detector may be of the typewhich is sensitive to a red light output. It should be noted thatalthough the micro-component displacement devices or arms 819 and 829have been described as mechanical in nature, they may also benon-mechanical, such as an intermittent fluid stream such as a gas orliquid stream or a light pulse such as a high-intensity laser pulse.

In another embodiment of the present invention, two substrates areprovided, wherein at least one of two substrates contain a plurality ofcavities. The two substrates are affixed together in the presence of atleast one plasma-forming gas so that when affixed, the cavities arefilled with the gas or gas mixture. In an embodiment of the presentinvention at least one electrode is disposed between the two substrates.In another embodiment, the inside, the outside, or both the inside andthe outside of the cavities are coated with at least one coating. It iscontemplated that any coating that may be applied to a micro-componentas disclosed herein may be used. As illustrated in FIG. 5, one method ofmaking a micro-component in accordance with this embodiment of thepresent invention is to take a first substrate 200 and a secondsubstrate 210 and then pass the first substrate 200 and the secondsubstrate 210 through a first roller assembly and a second rollerassembly, respectively. The first roller assembly includes a firstroller with nodules 224 and a first roller with depressions 228. Thefirst roller with nodules 224 is in register with the first roller withdepressions 228 so that as the first substrate 200 passes between thefirst roller with nodules 224 and the first roller with depressions 228,a plurality of cavities 240 are formed in the first substrate 200. Asmay be appreciated, the cavities may be in the shape desired formicro-components manufactured therewith such as hemispheres,capillaries, cylinders, etc. The second roller assembly, according to apreferred embodiment, includes two second rollers, 232 and 234. Thefirst substrate 200, with a plurality of cavities 240 formed therein, isbrought together with the second substrate 210 in the presence of aplasma-forming gas or gas mixture and then affixed, thereby forming aplurality of micro-components 250 integrally formed into a sheet ofmicro-components. While the first substrate 200 and the second substrate210 may be affixed by any suitable method, according to a preferredembodiment, the two substrates are thermally affixed by heating thefirst roller with depressions 228 and the second roller 234.

The nodules on the first roller with nodules 224 may be disposed in anypattern, having even or non-even spacing between adjacent nodules.Patterns may include, but are not limited to, alphanumeric characters,symbols, icons, or pictures. Preferably, the distance between adjacentnodules is approximately equal. The nodules may also be disposed ingroups such that the distance between one group of nodules and anothergroup of nodules is approximately equal. This latter approach may beparticularly relevant in color light-emitting panels, where each nodulein a group of nodules may be used to form a micro-component that isconfigured for red, green, and blue, respectively.

While it is preferred that the second roller assembly simply include twosecond rollers, 232 and 234, in an embodiment of the present inventionas illustrated in FIG. 6, the second roller assembly may also include asecond roller with nodules 236 and a second roller with depressions 238that are in registration so that when the second substrate 210 passesbetween the second roller with nodules 236 and the second roller withdepressions 238, a plurality of cavities 260 are also formed in thesecond substrate 210. The first substrate 200 and the second substrate210 are then brought together in the presence of at least one gas sothat the plurality of cavities 240 in the first substrate 200 and theplurality of cavities 260 in the second substrate 210 are in register.The two substrates are then affixed, thereby forming a plurality ofmicro-components 270 integrally formed into a sheet of micro-components.While the first substrate 200 and the second substrate 240 may beaffixed by any suitable method, according to a preferred embodiment, thetwo substrates are thermally affixed by heating the first roller withdepressions 228 and the second roller with depressions 238.

In an embodiment of the present invention that is applicable to the twomethods discussed above, and illustrated in FIG. 9, at least oneelectrode 280 is disposed on or within the first substrate 200, thesecond substrate 240 or both the first substrate and the secondsubstrate. Depending on how the electrode or electrodes are disposed,the electrode or electrodes will provide the proper structure for eitheran AC or DC (FIG. 7) light-emitting panel. That is to say, if the atleast one electrode 280 is at least partially disposed in a cavity 240or 260 then there will be a direct conductive path between the at leastone electrode and the plasma-forming gas or gas mixture and the panelwill be configured for D.C. If, on the other hand, the at least oneelectrode is disposed so as not to be in direct contact with theplasma-forming gas or gas mixture, the panel will be configured for A.C.

In another embodiment of the present invention, at least one substrateis thermally treated in the presence of at least one plasma-forming gas,to form a plurality of shells 50 filled with the plasma-forming gas orgas mixture. In a preferred embodiment of the present invention, asshown in FIG. 10, the process for making a micro-component would entailstarting with a material or material mixture 700, introducing inclusionsinto the material 710, thermally treating the material so that theinclusions start forming bubbles within the material 720 and thosebubbles coalesce 730 forming a porous shell 740, and cooling the shell.The process is performed in the presence of a plasma-forming gas so thatwhen the shell cools the plasma-forming gas 45 is sealed inside theshell 50. This process can also be used to create a micro-component witha shell doped with a conductive material and/or a secondary emissionenhancement material by combining the appropriate dopant with theinitial starting material or by introducing the appropriate dopant whilethe shell is still porous.

In a yet still further method of manufacture, the micro-components canbe manufactured using any of the above-mentioned methods, but not in thepresence of a plasma-forming gas, and either in a vacuum, air or otheratmosphere such as an inert atmosphere. They can be fabricated with oneor two openings, and the initial gas inside can be drawn out, forexample, through injection of plasma-forming gas through one opening,forcing the gas therein out the other opening. The openings can then besealed conventionally.

In yet another alternative method, a device having one or moremicro-pippettes can create the micro-components much like conventionalglass blowing. The gas used to effect the glass-blowing operation can beone of the aforementioned plasma-forming gasses.

In yet still another alternative, an optical fiber extrusion device canbe used to manufacture the micro-components. Like an optical fiber,which is solid, the device can be used to extrude a capillary which ishollow on the inside. The capillary can then be cut, filled withplasma-forming gas and sealed.

With respect to the selection of materials and dimensions for themicro-components manufactured in the manner described herein, they aremanufactured to meet requirements for various standard displayresolutions. FIG. 7 illustrates an example of calculation of pixel sizeand micro-component size, in the case where the micro-components arespheres, for 42-inch and 60-inch high definition television displayhaving a 16:9 aspect ratio. FIG. 8 is a table showing numbers of pixelsfor various standard display resolutions, and using the process formanufacturing in accordance with the invention herein, such standardscan be easily met.

In a further aspect, once the micro-components are manufactured, it isdesirable to condition them prior to assembly into a plasma displaypanel. By conditioning is meant exciting them for a time and at anexcitation sufficient to cause those micro-components which are likelyto fail a short time after assembly in a plasma display panel, to failprior to assembly. In this manner the yield relative to non-defectivemicro-components which are eventually assembled into a plasma displaypanel is significantly increased. Examples of devices for achieving saidconditioning are shown in FIGS. 11 and 12. As shown in the conditioningdevice 951 of FIG. 11 the manufactured and pretested micro-components959 can be assembled between two conducting metal plates 957 which arepowered through leads 955 by a voltage source 953 which can take variousforms as illustrated therein. The micro-components 959 are subjected toa field sufficient to excite the plasma gas contained therein, andpreferably at a level higher than any excitation level achieved whenassembled in a plasma display panel. This is done for a period of timesufficient such that any micro-components which are prone to fail, willfail during the conditioning phase, typically five to ten hours.

As may be appreciated, an alternative system is illustrated by FIG. 13which shows a conditioning device 901 which further includes a container909 for confining and containing micro-components 911. The container 909may be placed between parallel plates or electrodes 903 which arepowered through leads 905 by a power source 907 such as a voltage sourceof the type previously discussed with reference to FIG. 11. Theadvantage of such a system is that by having container 909, themicro-components are easily contained. After the conditioning period,the individual micro-components can then be dropped through a systemsuch as pretesting device 801 shown in FIG. 11 without the presence ofmanufacturing drop tower 600, and tested previously described for themethod during which the micro-components are assembled. In this manner,those micro-components which failed the conditioning are eliminated andonly fully-functioning micro-components can then be assembled into aplasma display panel as heretofore described.

With respect to micro-components manufactured as discussed withreference to FIGS. 5, 6, and 9, once assembled, they may be cut from thesheets on which they are formed. They can be pretested with a devicesuch as shown in the lower half of FIG. 11 at 801 and 803. They can thenbe pre-conditioned as previously described with reference to FIGS. 12and 13, and then retested with the device of the lower half of FIG. 11at 801 and 803.

Other embodiments and uses of the present invention will be apparent tothose skilled in the art from consideration of this application andpractice of the invention disclosed herein. The present description andexamples should be considered exemplary only, with the true scope andspirit of the invention being indicated by the following claims. As willbe understood by those of ordinary skill in the art, variations andmodifications of each of the disclosed embodiments, includingcombinations thereof, can be made within the scope of this invention asdefined by the following claims.

1-24. (canceled)
 25. A process for forming a micro-component,comprising: forming a shell of a predetermined shape; encapsulating aplasma-forming gas within the shell to produce the micro-component;testing the micro-component for a predetermined physical characteristic;and discarding the micro-component if the micro-component does not meetthe predetermined physical characteristic.
 26. The process of claim 25,further comprising: creating a liquid droplet in the presence of aplasma-forming gas; encasing the droplet with a material that forms theshell; and dehydrating the droplet encased with the material.
 27. Theprocess of claim 25, wherein forming the shell comprises forming theshell in the predetermined shape of a sphere.
 28. The process of claim25, wherein forming the shell comprises forming the shell in thepredetermined shape of a capillary.
 29. The process of claim 25, whereinforming the shell comprises glass blowing the shell with theplasma-forming gas.
 30. The process of claim 25, wherein forming theshell comprises forming the shell with an optical fiber extrusiondevice.
 31. The process of claim 25, wherein testing comprisesinspecting the micro-component for a physical defect.
 32. The process ofclaim 31, wherein discarding comprises discarding the micro-component ifthe micro-component has the physical defect.
 33. The process of claim25, wherein testing comprises exciting the plasma-forming gas.
 34. Theprocess of claim 25, wherein testing comprises detecting a luminousoutput from the micro-component.
 35. The process of claim 34, whereindiscarding the micro-component comprises discarding the micro-componentif the luminous output is below a threshold level.
 36. The process ofclaim 25, wherein the shell comprises two openings and encapsulating theplasma-forming gas comprises injecting the plasma-forming gas throughone of the two openings and sealing the two openings.
 37. The process ofclaim 25, wherein forming the shell comprises forming cavities in atleast one of two substrates and encapsulating comprises affixing the twosubstrates together in the presence of the plasma-forming gas.
 38. Theprocess of claim 25, further comprising coating the micro-component witha frequency converting coating.
 39. The process of claim 38, whereincoating comprises coating the micro-component with a rare earthmaterial.
 40. The process of claim 25, further comprising doping theshell with a conductive material.
 41. The process of claim 38, whereincoating comprises disposing the conductive material in at least twolocalized areas on the shell to provide conductive paths.
 42. Theprocess of claim 38, wherein coating comprises disposing the conductivematerial in the shell to produce anisotropic conductivity in the shell.43. The process of claim 25, wherein encapsulating comprisesencapsulating a rare gas halide.
 44. The process of claim 38, whereinthe coating comprises coating the shell with barium fluoride.
 45. Theprocess of claim 38, wherein coating comprises coating the shell withyttrium aluminum garnet.
 46. The process of claim 38, wherein coatingcomprises coating the shell with yttrium aluminum garnet doped withcerium.
 47. The process of claim 38, wherein coating comprises coatingthe shell with gadolinium gallium garnet.
 48. A process for testing aplurality of micro-components, comprising: selecting eachmicro-component for testing during a continuous process of manufacturingthe micro-components; optically inspecting each micro-component for astructural defect; and discarding any micro-component having thestructural defect.
 49. The process of claim 48, further comprisingapplying an excitation field to each micro-component to cause a plasmagenerating gas within each micro-component to become excited to emitradiation; and wherein optically inspecting comprises opticallyinspecting each micro-component to determine if each micro-componentdischarges the radiation and discarding comprises discarding anymicro-component that does not discharge the radiation.
 50. The processof claim 49, wherein applying the excitation field comprises excitingeach micro-component with an electron beam.
 51. The process of claim 49,wherein applying the excitation field comprises exciting eachmicro-component with a tesla coil.
 52. The process of claim 49, whereinapplying the excitation field comprises exciting each micro-componentwith a high frequency RF signal.
 53. A method for conditioning aplurality of micro-components for use in a plasma display, eachmicro-component emitting radiation when exposed to an excitation field,the method comprising: assembling the plurality of micro-components intoa batch; applying the excitation field to the batch of micro-componentsfor a predetermined amount of time; and terminating the excitation fieldand individually testing operation of each one of the micro-components.54. The method of claim 53, wherein individually testing comprisesdiscarding micro-components which fail to operate.
 55. The method ofclaim 53, wherein applying the excitation field comprises applying theexcitation field at a magnitude greater than a second excitation fieldwhich is applied to the micro-components when in the plasma display. 56.The method of claim 53, wherein applying the excitation field comprisesselecting the predetermined amount of time.